Iron-sulfur cluster assembly enzyme ISCU, mitochondrial (ISCU)

Scaffold protein for the de novo synthesis of iron- sulfur (Fe-S) clusters within mitochondria, which is required for maturation of both mitochondrial and cytoplasmic [2Fe-2S] and [4Fe-4S] proteins (PubMed:11060020). First, a [2Fe-2S] cluster is transiently constructed on the scaffold protein ISCU.

In another step, the cluster is released from ISCU, transferred to a glutaredoxin GLRX5, followed by the formation of mitochondrial [2Fe-2S] proteins, the synthesis of [4Fe-4S] clusters and their target-specific insertion into the receiver apoproteins. Cluster assembly on ISCU is dependent upon the function of the cysteine desulfurase complicated NFS1-LYRM4/ISD11, which serves as the sulfur donor for cluster synthesis, the iron-binding protein frataxin as the putative iron donor, as well as the electron transport chain comprised of ferredoxin reductase and ferredoxin, which receive their electrons from NADH (By similarity).